Effect of Water Activity and Temperature on Aflatoxin Production by Aspergillus parasiticus

1976 ◽  
Vol 39 (3) ◽  
pp. 170-174 ◽  
Author(s):  
M. D. NORTHOLT ◽  
C. A. H. VERHULSDONK ◽  
P. S S. SOENTORO ◽  
W. E. PAULSCH
Keyword(s):  
Water Activity ◽  
Aflatoxin B1 ◽  
Mycelial Growth ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Optimal Temperature ◽  
Strong Inhibition ◽  
Submerged Cultures ◽  
Effect Of Water ◽  
Agar Media

The effect of water activity (aw) on growth and aflatoxin production by Aspergillus parasiticus NRRL 2999 was determined using submerged cultures in which the aw was adjusted by addition of glycerine, glucose, or a mixture of salts. At a sub-optimal aw aflatoxin production was low in the glycerol and glucose media while no strong inhibition of mycelial growth occurred. A similar effect was obtained in surface cultures on agar media in which the aw was adjusted by addition of glycerine or sucrose. The effect of a sub-optimal temperature was the reverse; compared to inhibition of mycelial growth in surface cultures, the effect on aflatoxin production was slight. No detectable quantities of aflatoxin B1 were formed at 0.83 aw and at 10 C nor at four combinations of higher aw and temperature. The aw was measured by a recently developed device using the dewpoint principle.

Effects of Potassium Sorbate on Growth and Aflatoxin Production by Aspergillus parasiticus and Aspergillus flavus1

1983 ◽  
Vol 46 (11) ◽  
pp. 940-942 ◽  
Author(s):  
LLOYD B. BULLERMAN
Keyword(s):  
Aspergillus Flavus ◽  
Yeast Extract ◽  
Aflatoxin B1 ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Potassium Sorbate ◽  
Mycelial Mass ◽  
Yeast Extract Sucrose

Growth and aflatoxin production by selected strains of Aspergillus parasiticus and Aspergillus flavus in the presence of potassium sorbate at 12°C were studied. Potassium sorbate at 0.05, 0.10 and 0.15% delayed or prevented spore germination and initiation of growth, and slowed growth of these organisms in yeast-extract sucrose broth at 12°C. Increasing concentrations of sorbate caused more variation in the amount of total mycelial growth and generally resulted in a decrease in total mycelial mass. Potassium sorbate also greatly reduced or prevented production of aflatoxin B1 by A. parasiticus and A. flavus for up to 70 d at 12°C. At 0.10 and 0.15% of sorbate, aflatoxin production was essentially eliminated. A 0.05% sorbate, aflatoxin production was greatly decreased in A. flavus over the control, but only slightly decreased in A. parasiticus.

Growth and Aflatoxin Production by Aspergillus parasiticus NRRL 2999 in the Presence of Acetic or Propionic Acid and at Different Initial pH Values

1987 ◽  
Vol 50 (11) ◽  
pp. 909-914 ◽  
Author(s):  
GULAM RUSUL ◽  
FATHY E. EL-GAZZAR ◽  
ELMER H. MARTH
Keyword(s):  
Acetic Acid ◽  
Propionic Acid ◽  
Aflatoxin B1 ◽  
Maximum Concentration ◽  
Aspergillus Parasiticus ◽  
Dry Weight ◽  
Aflatoxin Production ◽  
Lag Phase ◽  
Significant Difference ◽  
Initial Ph

Experiments were done to determine effects of different concentrations of acetic or propionic acid in a glucose-yeast extract-salts medium with an initial pH value of 4,5 or 5.5 on growth and aflatoxin production by Aspergillus parasiticus NRRL 2999. Amounts of aflatoxin were measured with reversed-phase high-performance liquid chromatography. The maximum concentration of acetic or propionic acid that permitted growth at an initial pH of 5.5 was 1% after 7 d of incubation and 0.25% after 3 d of incubation, respectively. When the initial pH of the medium was 4.5, the maximum concentration of acetic or propionic acid that permitted growth was 0.25 or 0.1%, respectively. There was no significant difference (p>0.05) in amount of mycelial (dry weight) produced by cultures in the presence of 0.0, 0.25, 0.50 or 0.75% acetic acid. Amounts of aflatoxin B1 and G1 produced decreased with an increasing concentration of acetic acid. Increasing concentrations of propionic acid caused a decrease in the amount of mycelial dry weight and aflatoxin produced by cultures growing in the medium with an initial pH of 5.5. At an initial pH of 4.5 mycelial growth was slow and at 3 d of incubation amounts of aflatoxin B1 and G1 produced were reduced as concentrations of acetic acid increased. This also was true for propionic acid in the medium with an initial pH of 4.5. Cultures with an extended lag phase in the presence of acetic or propionic acid overcame this and then produced large amounts of aflatoxin B1 and G1 at 7 and 10 d of incubation.

Aflatoxigenic Potential for Aspergilli on Sucrose Substrates

1980 ◽  
Vol 63 (3) ◽  
pp. 622-625
Author(s):  
Gerald C Llewellyn ◽  
Hudson C Jones ◽  
James E Gates ◽  
Thomas Eadie
Keyword(s):  
Carbon Source ◽  
Mycelial Growth ◽  
Aspergillus Parasiticus ◽  
Growth Period ◽  
Aflatoxin Production ◽  
Food And Drink

Abstract Sucrose concentrations of 3, 10, 20, and 30% in Czapek Dox broth served as the carbon source for growth, aflatoxin production, and sporulation for Aspergillus parasiticus NRRL 2999 and A flavus NRRL 3557, 5862, and 5013. All cultures produced mycelial growth and sporulated in all sucrose concentrations during the 12-day growth period. The area of mycelial mat coverage per hour increased directly with increased sugar concentrations. The 20 and 30% sucrose concentrations inhibited mycelial growth for 5862. The 30% sucrose cultures of 3557 and 5862 failed to produce detectable levels of aflatoxins. All other isolates produced B1 and G1 in an approximately 4:1 ratio in all sucrose concentrations. Only 2999 was a substantial producer of aflatoxin in all 4 sucrose cultures, ranging from 72 to 96 μg/mL medium. A. flavus 5013 produced the most toxin, 144 and 126 μg/mL medium in the 10 and 20% sucrose cultures, respectively. The 10 and 20% sucrose cultures were most conducive to aflatoxin production. Since these sucrose levels correspond closely to the levels in many food and drink products, especially home-made products, care and attention should be taken to keep them free of aflatoxigenic spores. Extensive mycelial growth and sporulation, even in aflatoxigenic strains, do not necessarily result in comparably high aflatoxin levels. Routine extraction and quantitation procedures for aflatoxin were applicable and provided satisfactory results.

Growth and Synthesis of Aflatoxin by Aspergillus parasificus in the Presence of Ginseng Products

1983 ◽  
Vol 46 (3) ◽  
pp. 210-215 ◽  
Author(s):  
JAERIM BAHK ◽  
ELMER H. MARTH
Keyword(s):  
Aflatoxin B1 ◽  
Mycelial Growth ◽  
Aflatoxin Production ◽  
Mold Growth ◽  
Red Ginseng ◽  
Maximum Accumulation ◽  
Ginseng Saponin ◽  
White Ginseng

Red ginseng saponin (0.36%) inhibited mycelial growth, sporulation and aflatoxin production by Aspergillus parasificus during 9 d at 28°C. The mold caused no change in pH of the medium when it contained red ginseng saponin or ginseng tea (9%). Most ginseng products permitted mycelial growth and production of aflatoxin B1, but inhibited production of aflatoxin G1. However, when compared to the control, aflatoxin production by A. parasiticus was reduced by the presence in the medium of most of the ginseng products that were tested, Ginseng tea (9%) resulted in a higher index of maximum accumulation of aflatoxins per interval of mold growth than occurred in the control. Red ginseng was more effective than white ginseng for inhibiting mold growth and aflatoxin production.

scholarly journals Antifungal Activity and Aflatoxin Degradation of Bifidobacterium Bifidum and Lactobacillus Fermentum Against Toxigenic Aspergillus Parasiticus

2016 ◽  
Vol 10 (1) ◽  
pp. 197-201 ◽  
Author(s):  
Roshanak Daie Ghazvini ◽  
Ebrahim Kouhsari ◽  
Ensieh Zibafar ◽  
Seyed Jamal Hashemi ◽  
Abolfazl Amini ◽  
...  
Keyword(s):  
Mycelial Growth ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Hplc Method ◽  
Bifidobacterium Bifidum ◽  
Lactobacillus Fermentum ◽  
Inhibition Rate ◽  
Plate Method ◽  
Mycelial Mass ◽  
Yeast Extract Sucrose

Food and feedstuff contamination with aflatoxins (AFTs) is a serious health problem for humans and animals, especially in developing countries. The present study evaluated antifungal activities of two lactic acid bacteria (LAB) against growth and aflatoxin production of toxigenic Aspergillus parasiticus. The mycelial growth inhibition rate of A. parasiticus PTCC 5286 was investigated in the presence of Bifidobacterium bifidum PTCC 1644 and Lactobacillus fermentum PTCC 1744 by the pour plate method. After seven days incubation in yeast extract sucrose broth at 30°C, the mycelial mass was weighed after drying. The inhibitory activity of LAB metabolites against aflatoxin production by A. parasiticus was evaluated using HPLC method. B. bifidum and L. fermentum significantly reduced aflatoxin production and growth rate of A. parasiticus in comparison with the controls (p≤0.05). LAB reduced total aflatoxins and B1, B2, G1 and G2 fractions by more than 99%. Moreover, LAB metabolites reduced the level of standard AFB1, B2, G1 and G2 from 88.8% to 99.8% (p≤0.05). Based on these findings, B. bifidum and L. fermentum are recommended as suitable biocontrol agents against the growth and aflatoxin production by aflatoxigenic Aspergillus species.

Growth and spore production of Plectosporium tabacinum

2001 ◽  
Vol 79 (11) ◽  
pp. 1297-1306 ◽  
Author(s):  
Wenming Zhang ◽  
Michelle Sulz ◽  
Karen L Bailey
Keyword(s):  
Carbon Source ◽  
Carbon Concentration ◽  
Mycelial Growth ◽  
Liquid Culture ◽  
C:N Ratio ◽  
Spore Production ◽  
Optimal Temperature ◽  
Agar Media ◽  
Galium Spurium ◽  
Optimal Ph

Plectosporium tabacinum (van Beyma) M.E. Palm, W. Gams, et Nirenberg has been evaluated as a bioherbicide for the control of Galium spurium L. (false cleavers). Little is known, however, about the specific culture and sporulation requirements of this fungus on standard agar media. In addition, information on submerged liquid culture spore production is not available. This information is important for the successful culture and further development of this fungus as a biocontrol agent. This study characterized mycelial growth and sporulation of Plectosporium tabacinum on 14 different standard agar media over a range of light regimes, pH, and temperatures. Conditions required for submerged liquid culture spore production and resulting weed control efficacy were also assessed. This included the effect of liquid culture medium and pH and the effect of carbon source, nitrogen source, carbon concentration, and carbon–nitrogen (C:N) ratio. Potato dextrose agar is the best agar medium for growth and spore production. On standard agar media, growth and spore production was not influenced by light regime. Medium pH did not affect mycelial growth and spore germination but the optimal pH for spore production was 7.0. The optimal temperature for the mycelial growth was between 22 and 25°C, but the optimal temperature for spore production was at either 20 or 30°C, depending upon the nutrient medium. Temperatures above 20°C were required to achieve greater than 90% spore germination. For submerged liquid culture spore production, Richard's solution (RS) is the best liquid medium for spore production. The optimal pH was 7.0 for RS but varied with culture media. Potassium nitrate and corn starch were the best nitrogen source and carbon source, respectively. A medium with a carbon concentration of 12.6 g/L and a C:N ratio of 7.5:1 is optimum for spore production and weed control efficacy.Key words: Plectosporium tabacinum, bioherbicide, mass production, fermentation, false cleavers, Galium spurium.

Differences Between Aspergillus flavus Strains in Growth and Aflatoxin B1 Production in Relation to Water Activity and Temperature

1977 ◽  
Vol 40 (11) ◽  
pp. 778-781 ◽  
Author(s):  
M. D. NORTHOLT ◽  
H. P. van EGMOND ◽  
W. E. PAULSCH
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Water Activity ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Toxin Production ◽  
Fast Growth ◽  
Temperature Optimum ◽  
Agar Media ◽  
Stimulation Of

The optimum and limiting conditions of water activity (aw) and temperature for growth of and aflatoxin B1 production by various Aspergillus flavus strains were determined. Agar media were used in which the aw was adjusted by addition of sucrose or glycerine. Optimum temperatures for aflatoxin B1 production at high aw varied with the strain tested being 13–16, 16–24, or 31 C. Strains with a low temperature optimum for aflatoxin B1 production showed fast growth at 37 C without aflatoxin B1 production. A reduced aw (0.95 and less) together with a moderate or low temperature inhibited toxin production more than growth. However, at a high temperature one strain showed stimulation of aflatoxin B1 production on the glycerine medium at reduced aw No differences were noted between aflatoxinpositive and aflatoxin-negative strains with respect to growth under various conditions.

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